/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.io;

/**
 * Constants written into the Object Serialization Stream.
 *
 * @author unascribed
 * @since JDK 1.1
 */
public interface ObjectStreamConstants {

  /**
   * Magic number that is written to the stream header.
   */
  final static short STREAM_MAGIC = (short) 0xaced;

  /**
   * Version number that is written to the stream header.
   */
  final static short STREAM_VERSION = 5;

    /* Each item in the stream is preceded by a tag
     */

  /**
   * First tag value.
   */
  final static byte TC_BASE = 0x70;

  /**
   * Null object reference.
   */
  final static byte TC_NULL = (byte) 0x70;

  /**
   * Reference to an object already written into the stream.
   */
  final static byte TC_REFERENCE = (byte) 0x71;

  /**
   * new Class Descriptor.
   */
  final static byte TC_CLASSDESC = (byte) 0x72;

  /**
   * new Object.
   */
  final static byte TC_OBJECT = (byte) 0x73;

  /**
   * new String.
   */
  final static byte TC_STRING = (byte) 0x74;

  /**
   * new Array.
   */
  final static byte TC_ARRAY = (byte) 0x75;

  /**
   * Reference to Class.
   */
  final static byte TC_CLASS = (byte) 0x76;

  /**
   * Block of optional data. Byte following tag indicates number
   * of bytes in this block data.
   */
  final static byte TC_BLOCKDATA = (byte) 0x77;

  /**
   * End of optional block data blocks for an object.
   */
  final static byte TC_ENDBLOCKDATA = (byte) 0x78;

  /**
   * Reset stream context. All handles written into stream are reset.
   */
  final static byte TC_RESET = (byte) 0x79;

  /**
   * long Block data. The long following the tag indicates the
   * number of bytes in this block data.
   */
  final static byte TC_BLOCKDATALONG = (byte) 0x7A;

  /**
   * Exception during write.
   */
  final static byte TC_EXCEPTION = (byte) 0x7B;

  /**
   * Long string.
   */
  final static byte TC_LONGSTRING = (byte) 0x7C;

  /**
   * new Proxy Class Descriptor.
   */
  final static byte TC_PROXYCLASSDESC = (byte) 0x7D;

  /**
   * new Enum constant.
   *
   * @since 1.5
   */
  final static byte TC_ENUM = (byte) 0x7E;

  /**
   * Last tag value.
   */
  final static byte TC_MAX = (byte) 0x7E;

  /**
   * First wire handle to be assigned.
   */
  final static int baseWireHandle = 0x7e0000;

  /******************************************************/
    /* Bit masks for ObjectStreamClass flag.*/

  /**
   * Bit mask for ObjectStreamClass flag. Indicates a Serializable class
   * defines its own writeObject method.
   */
  final static byte SC_WRITE_METHOD = 0x01;

  /**
   * Bit mask for ObjectStreamClass flag. Indicates Externalizable data
   * written in Block Data mode.
   * Added for PROTOCOL_VERSION_2.
   *
   * @see #PROTOCOL_VERSION_2
   * @since 1.2
   */
  final static byte SC_BLOCK_DATA = 0x08;

  /**
   * Bit mask for ObjectStreamClass flag. Indicates class is Serializable.
   */
  final static byte SC_SERIALIZABLE = 0x02;

  /**
   * Bit mask for ObjectStreamClass flag. Indicates class is Externalizable.
   */
  final static byte SC_EXTERNALIZABLE = 0x04;

  /**
   * Bit mask for ObjectStreamClass flag. Indicates class is an enum type.
   *
   * @since 1.5
   */
  final static byte SC_ENUM = 0x10;


    /* *******************************************************************/
    /* Security permissions */

  /**
   * Enable substitution of one object for another during
   * serialization/deserialization.
   *
   * @see java.io.ObjectOutputStream#enableReplaceObject(boolean)
   * @see java.io.ObjectInputStream#enableResolveObject(boolean)
   * @since 1.2
   */
  final static SerializablePermission SUBSTITUTION_PERMISSION =
      new SerializablePermission("enableSubstitution");

  /**
   * Enable overriding of readObject and writeObject.
   *
   * @see java.io.ObjectOutputStream#writeObjectOverride(Object)
   * @see java.io.ObjectInputStream#readObjectOverride()
   * @since 1.2
   */
  final static SerializablePermission SUBCLASS_IMPLEMENTATION_PERMISSION =
      new SerializablePermission("enableSubclassImplementation");
  /**
   * A Stream Protocol Version. <p>
   *
   * All externalizable data is written in JDK 1.1 external data
   * format after calling this method. This version is needed to write
   * streams containing Externalizable data that can be read by
   * pre-JDK 1.1.6 JVMs.
   *
   * @see java.io.ObjectOutputStream#useProtocolVersion(int)
   * @since 1.2
   */
  public final static int PROTOCOL_VERSION_1 = 1;


  /**
   * A Stream Protocol Version. <p>
   *
   * This protocol is written by JVM 1.2.
   *
   * Externalizable data is written in block data mode and is
   * terminated with TC_ENDBLOCKDATA. Externalizable class descriptor
   * flags has SC_BLOCK_DATA enabled. JVM 1.1.6 and greater can
   * read this format change.
   *
   * Enables writing a nonSerializable class descriptor into the
   * stream. The serialVersionUID of a nonSerializable class is
   * set to 0L.
   *
   * @see java.io.ObjectOutputStream#useProtocolVersion(int)
   * @see #SC_BLOCK_DATA
   * @since 1.2
   */
  public final static int PROTOCOL_VERSION_2 = 2;
}
